Query a BLAST database with an accession, but exclude that accession from the results

# Extract a GI from the ecoli database:
$ blastdbcmd -entry all -db ecoli -dbtype nucl -outfmt %a | head -1 | \
  tee exclude_me 
AE000111.1
# Run the restricted database search, which shows there are no self-hits:
$ blastn -db ecoli -negative_seqidlist exclude_me -show_gis -num_alignments 0 \
  -query exclude_me | grep `cat exclude_me`
Query= AE000111.1 Escherichia coli K-12 MG1655 section 1 of 400 of the 
$